There’s been a lot of shouting about Obamacare in the news lately but much less discussion of the basics of the program. That’s led to confusion among many Americans as to what the new health-care law will (or will not) require them to do.

To try and help remedy this situation we’re going to explain in simple language important aspects of the Affordable Care Act, known informally as Obamacare. We’ll start with a basic question many folks are asking on the Internet: When does Obamacare start?

We’ll start with the bottom line: the preliminaries, the pre-game if you will, have already begun. But the main event does not get going until the beginning of next year.

Obamacare’s first key date was Oct. 1 of this year. That’s when the state exchanges were supposed to open for enrollment. These are health insurance marketplaces intended for people who buy health coverage on their own, as opposed to getting it through an employer.

(The federal government is going to help many middle-income and lower-income Americans pay for insurance purchased through exchanges. We’ll discuss who is eligible for these subsidies in another post.)

You may have heard that a lot of these online exchanges had problems in their first weeks. People have had a hard time signing in, establishing accounts, and sending their information to insurance companies. The Obama administration has vowed that these glitches will be fixed by November 30. Some experts think they might persist after that.

Anyway, the exchanges are where you’re supposed to shop for insurance, compare plans, and decide which is best for you and your family. That brings us to the next key date: Dec. 15.

Dec. 15 is an intermediate deadline. If you’re buying insurance through the exchanges, that’s the last day you can press the “purchase” button and expect that your new policy will take effect by Jan. 1.

And Jan. 1, 2014 is kickoff time. That’s the day Obamacare is supposed to truly and fully be open for business. That means it is also the first day the federal government will require most Americans to have health insurance. That’s why you should buy your policy by mid-December if you’re shopping in the exchange marketplaces.

But Uncle Sam will cut you some slack this year, since Obamacare marks a big change in the way health insurance is bought and sold in the US. For 2014 only, open enrollment won’t end until March 31.

That means you can wait until March 31 to buy individual health policies through the exchanges. You won’t have to pay a tax penalty, even if you didn’t have health coverage the first months of the year.

After April 1 the penalty kicks in. That’s because of the new US requirement that you have health insurance, remember. It’s often called the “individual mandate.” If you’re uncovered the IRS will assess the penalty on your 2014 taxes, which are due on April 15, 2015.

That’s pretty much it for the important upcoming Obamacare dates. Remember, you’ll still be able to buy coverage through the exchanges after April 1 if your life situation changes in a big way. Divorce, marriage, and job loss are among the things that qualify as big changes.

There are also some exceptions to the stuff outlined above. Native Americans, for instance, can buy health insurance through the exchanges throughout the year. Lower-income Americans who qualify for Medicaid can sign up for that program at any point. They’re not subject to the exchange open enrollment deadlines.

Finally, it’s possible all these dates could get pushed back. Many critics are now saying the implementation of Obamacare should be delayed until the websites are running better. The White House insists it won’t do that, though. The program is so intricate that delay would cause lots of new problems.

If you want information about your specific circumstances go to healthcare.gov. That’s the website that is also supposed to guide you to state exchanges (when it’s working). Another good place to look is at the Kaiser Family Foundation website. That’s a source from outside government with lots of good advice about how to navigate through the brave new health-care world.